Effect Of Electric Field Treatment On The Structure,Function,and Volatile Flavor Compounds Of Pea Protein

With the progress of social development,concepts such as healthy diet and green sustainable development have been widely recognized.Compared to traditional meat,plantbased meat has advantages such as rich nutrition,environmental friendliness,and saving production factors.Pea protein is highly favored and concerned by consumers both domestically and internationally due to its high yield,abundant resources,high nutritional value,and low allergenicity.However,the poor functional properties of pea protein limit its application in the field of plant-based meat products.In this paper,pea protein was taken as the research object,and the effects of PEF,DCEF and ACEF treatment on the structure,functional properties and volatile flavor substances of pea protein were studied by using Fourier transform infrared spectroscopy(FT-IR),fluorescence spectroscopy,gas chromatography-mass spectrometer(GC-MS)and other instruments.To provide theoretical basis and technical support for the development of plant-based meat products using pea protein as raw material.The main research findings are as follows:1 Pulse electric field(PEF)treatment has a significant impact on the structure,function,and volatile substances of pea protein.(1)PEF treatment changed the partial structure of pea protein,but did not markedly affect the molecular weight and protein composition of pea protein;The FT-IR results indicate that the amide Ⅰ band,amide Ⅲ band,amide A band,and amide B band of pea protein undergo varying degrees of deviation,the effect on the secondary structure content of pea protein was mainly manifested in the decrease of α-helix and the increase and decrease of random coils structure;endogenous fluorescence spectroscopy,ultraviolet fluorescence spectroscopy,and surface hydrophobicity tests showed that the tertiary structure of treated pea protein underwent varying degrees of folding and aggregation,with an increase in ion bonds and a decrease in hydrogen bonds,while reducing hydrophobic interactions;the content of free thiol groups decreases,while the content of disulfide bonds increases.(2)PEF treatment changed the functional properties of pea protein.After PEF treatment,the water holding capacity of pea protein increases,oil holding capacity decreases,emulsifying capacity decreases,and emulsifying stability increases.(3)PEF treatment changed the relative content of volatile flavor compounds in pea protein.The GC-MS results showed that the content of alkanes,alcohols,and aldehydes in pea protein increased after pulse electric field treatment,while some new substances were produced,mainly ethers and ketones.2 Direct current electric field(DCEF)treatment has a significant impact on the structure,function,and volatile flavor compounds of pea protein.(1)DCEF treatment changed the partial structure of pea protein,and the number of small molecules in pea protein increased under conditions of electric field intensity of 3.25 kV/cm,3.5 kV/cm,and treatment time of 15 minutes;the FT-IR results indicate that the amide I band,amide A band,and amide B band of pea protein undergo varying degrees of deviation,the effect on the secondary structure content of pea protein is mainly manifested in the increase of β-sheet,the decrease of α-helix,the decrease of random coil structure and the increase ofβ-turn;endogenous fluorescence spectroscopy,ultraviolet fluorescence spectroscopy,and surface hydrophobicity tests showed that the tertiary structure of pea protein after treatment unfolded to varying degrees,with an increase in ion bonds,a decrease in hydrogen bonds,and an increase in hydrophobic interactions;The content of free thiol groups increases,while the content of disulfide bonds decreases.(2)DCEF treatment changed the functional properties of pea protein.After DCEF treatment,the water and oil holding capacity of pea protein increased,enhancing its emulsifying ability and emulsifying stability.(3)DCEF treatment changed the relative content of volatile flavor compounds in pea protein.The GC-MS results showed that after treatment,the content of alcohols,ketones,alkanes,and olefins in pea protein decreased,while the content of aldehydes increased.At the same time,some new substances,mainly ethers and esters,were produced.3 Alternating current electric field(ACEF)treatment has a significant impact on the structure,function,and volatile flavor compounds of pea protein.(1)ACEF treatment changed the partial structure of pea protein,and the number of small molecules in pea protein increased under conditions of electric field intensity of 15 V/cm,20 V/cm,and treatment time of 200 seconds;The FT-IR results showed that there was a partial blue shift in the amide Ⅱ and amide Ⅲ bands(about 2/cm),a blue shift in the amide A band(about 2/cm),and a red shift in the amide B band.The maximum red shift(about 8/cm)was observed at 400 seconds of ACEF treatment,and the effects on the secondary structure content of pea protein were mainly manifested in the increase of β-fold,α-helix and β-rotation;endogenous fluorescence spectra,ultraviolet fluorescence spectra,and surface hydrophobicity tests showed that the tertiary structure of pea protein after treatment underwent varying degrees of changes,with an increase in ion bonds and a decrease in hydrogen bonds,while the changes in hydrophobic interactions were not significant;the content of free thiol groups decreases,while the content of disulfide bonds increases.(2)ACEF treatment changed the functional properties of pea protein.After ACEF treatment,the water holding capacity of pea protein increased and the oil holding capacity decreased;As the processing time increases,the emulsifying ability and emulsifying stability also increase.(3)ACEF treatment changed the relative content of volatile flavor compounds in pea protein.The results of GC-MS showed that the relative content of alkanes,alcohols,and aldehydes in the treated pea protein increased,while the content of alkenes and ketones decreased.At the same time,some new substances were produced,mainly ethers such as ethylene glycol monobutyl ether and esters such as ethyl hexanoate.4 After the pea protein was treated by different electric fields,the protein structure changed to different degrees,and its functional properties and volatile flavor substances also changed accordingly.The water holding,oil holding,and emulsifying properties of pea protein treated with direct current electric field were significantly improved,and the relative content of volatile flavor compounds in pea protein treated with direct current electric field was reduced.Accordingly,direct current electric field treatment can be used as an effective auxiliary method for the application of pea protein in vegetable meat raw materials.